Termi-nation

The wood-chomping pests rear their heads, but it's not all bad news

More on that later. First, there's the pressing issue of those swarmers, which are likely to appear in greater numbers this spring than in the recent past, thanks to a couple stretches of heavy rain this season.

“With the drought, we've generally had only minor swarms over the past few years,” said Michael Rust, a professor of entomology at the University of California Riverside. “But we've had some heavy rains this year, and I think if we see another good rainfall or two, there will be some pretty large swarms.”

Of the roughly 2,500 known species of termites in the world, 17 live in California. Termites can be lumped into four basic groups: mound builders, dampwood, drywood and subterranean. There are no mound-building species in North America, and dampwood termites are restricted primarily to Northern California, Oregon and Washington.

However, the last two – drywood and subterranean – are abundant in Southern California and San Diego County. A quick primer:

Termites are ancient insects, having been around for more than 100 million years. Like ants (which, incidentally, are their mortal enemies), termites are social organisms, forming collaborative colonies consisting of an egg-laying queen, a doting king, some pincer-headed soldiers for defense and myriad workers who pretty much operate the colony.

Western subterranean termites build their nests in soft soil below the frost line but above the water table, always in contact with edible wood. This may be a dead tree, a fence post or your house. They require a moist environment and are often drawn to structures with leaky plumbing.

A colony, with a queen laying up to 2,000 eggs a day, may number in the hundreds of thousands. Workers, who are most plentiful and do the most structural damage, are one-eighth of an inch long, creamy and translucent, blind, sterile and wingless. They work without respite for their entire 2-year life span.

The most obvious sign of an active termite nest is when swarming occurs. For western subterranean termites, this generally happens after sufficient rainfall and the first warm weather. “Though occasionally you'll see a swarm prompted by irrigation or someone watering their lawn,” said Vernard Lewis, an entomologist at the University of California Berkeley.

Swarming termites, called alates, are often mistaken for winged ants. Both are dark brown and about a half-inch long, but there are distinctive differences. Alates have straight antennae; ant antennae are bent or elbowed. Termite bodies are broad-waisted; ants' are pinched. Both insects sport two pairs of smoke-colored wings, but termite wings are all of equal length and noticeably veined. In ants, the rear pair of wings is shorter and there are fewer veins.

When swarming alates land, they quickly shed their wings, seek a mate and go to ground, digging an initial chamber in which to begin a new colony. Often, said Todd Veden, a technical specialist with the pest control company Terminix, the only evidence of alates are those discarded wings.

“In these cases, you look to see if there is a mix of sizes or if they're all the same length” to determine if the wings came from ants or termites.